Chemically converted graphene (CCG) was found to effectively quench the fluorescence emission of Cy3 dye 1 (the intensity is down to 1/38 of 1 alone) in aqueous solution, due to the formation of CCG-1 hybrid. After addition of certain amount of bovine serum albumin (BSA) into the above mentioned system, about 60 times of fluorescence enhancement was observed for the hybrid of CCG-1. This has been employed to discriminate BSA, and the fluorescence intensity was found to be proportional to the BSA added in a concentration range from 0 to 8×10-6 M, the BSA detection limit was down to 5×10-8 M. Meanwhile, the fluorescence of Ru(phen)3Cl2 (tris(1,10-phenanthroline)ruthenium(II) dichloride) can be effectively quenched with addition of graphene oxide (GO) in aqueous solution, due to the formation of GO-Ru hybrid. A fluorescence enhancement of approximately 50 times can be observed after the addition of certain amount of DNA into the above mentioned solution. The fluorescence increase is linearly proportional to the amount of DNA added in the concentration range of 0-70 μM and the DNA detection limit is down to 3.3×10-8 M. Furthermore, it is found that GO-Ru hybrid can enter into the nuclei and stain DNA of living human breast cancer cells MCF-7, while Ru(phen)3Cl2 alone cannot cross cellular membrane in the control experiment. This method can be employed to detect DNA both in vitro and in vivo. All these provide insight into rational design of efficient CCG/GO-based dyes delivery systems for biological applications.

Interaction of fluorescence dyes with CCG and GO

250th National Meeting (2015)

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